Out of the the box, the V2 Exadata supported 188.8.131.52. The latest Exadata servers (X2-2 and X2-8) are installed with 184.108.40.206, and 220.127.116.11 once it's supported on Exadata. It's not possible to run 10g using Exadata storage.
Both oracle database versions 18.104.22.168 and 22.214.171.124 are currently supported.
Since September 2011, no new exadata bundle patches for 126.96.36.199 are issued by oracle.
Exadata certification/support for 188.8.131.52 is pending, as andy indicated.